Page:The American Cyclopædia (1879) Volume VI.djvu/86

 78 DIAPHORETICS DIAPHRAGM her husband died, and Diana, putting on widow's weeds, expressed a resolve to wear them till her death; but this did not prevent her when nearly 40 years old from becoming the mistress of the dauphin (her junior by nearly 20 years), afterward Henry II. The duchess d'tampes then possessed the affec- tions of Francis I., and the two favorites divided the court until the accession of the dauphin in 1547, when Diana became almost mistress of the kingdom, and her rival was sent into exile. The beauty and accomplish- ments of the young queen, Catharine de' Medici, could not prevail against her influence. The king delighted in giving public tokens of his infatuation, admitted her to his councils, and in 1548 created her duchess of Valenti- nois. She retained her ascendancy until Hen- ry's death in 1559, when she retired to the palace built for her by her royal lover at Anet; but in 1561 she was recalled by Catharine de' Medici to exert her influence in detaching the constable de Montmorency from the Chatillons. From that time until her death she remained in retirement. Her power over the king, even when she had reached the age of 60, was due no less to her beauty than to her intellect. She spent large sums in charity. DIAPHORETICS (Gr. diafopsiv, to carry through), medicines or agents which promote perspiration. (See PERSPIRATION.) The skin is one of the channels for the discharge of sa- line substances, and therefore these, particu- larly the salts of the alkalies, are promoters of the sudoriferous action of the skin. To fa- cilitate their action, the skin should be kept warm and the body in a recumbent position. Bathing with tepid water, as tending to pro- duce exosmose through the glandular mem- brane, is also favorable. Among the most im- portant diaphoretic saline medicines are tartar emetic, or the double tartrate of antimony and potash, the carbonates of soda, potash, and ammonia, and sulphate of potash, which is one of the constituents of Dover's powder. The tartar emetic is one of the most powerful, and may be used to assist the action of other dia- phoretics by producing relaxation, and narcot- ics may be used for the same purpose. Among vegetable diaphoretics may be mentioned ipecacuanha, another constituent of Dover's powder, guaiacum, and camphor. It must not be forgotten that water, forming as it does nearly the whole of the perspiration, is per- haps the most powerful as well as safest of all diaphoretics, aided as it may be by warmth, exercise, and friction, and that it should nearly always form an important adjunct to the ad- ministration of medicinal diaphoretics. DIAPHRAGM, the transverse muscle which separates the thoracic from the abdominal cavity in mammalian vertebrates. It is flat- tened, nearly circular, fleshy at the edges ten- dinous in the centre, elongated, and ends in a point behind. In front it is attached to the ensiform cartilage of the breast bone on the sides to the internal surface of the last six ribs, behind to the transverse process of the first lumbar vertebra and to the bodies of the first three vertebras of the loins by tendinous slips; the fleshy fibres of the last form the pillars of the diaphragm, and their fasciculi cross each other in such a way as to leave two openings, one superior and anterior, giving passage to the oesophagus and par vagum nerve, the other interior, for the passage of the aorta, thoracic duct, and vena azygos ; the tendinous centre has been compared in shape to a leaf of clover. Between the middle and right portion of the tendinous centre is the opening for the passage of the inferior vena cava. The diaphragm is in relation, above, with the pericardium in the middle, and with the pleurae, base of the lungs, and walls of the chest on the sides ; below, with the aorta in the middle, the kidneys, renal capsules, pancreas, and duodenum ; on the right side with the liver, and on the left with the stomach and spleen. The direction of the posterior fibres is nearly vertical ; all the others converge toward the tendinous cen- tre. The diaphragm is the great muscle of respiration ; when it contracts, its central ten- The Diaphragm viewed from the Lower or Abdominal Side. V. C. /., the vena cava inferior ; <Z"., the oesophagus ; Ao., the aorta; Th. D., the thoracic duct, cut where they pass through the diaphragm, the broad white tendinous middle of which is easily distinguished from the radiating muscu- lar fibres which pass down to the ribs and into the pillars in front of the vertebrae. dinous portion is drawn downward, the cav- ity of the chest is enlarged, and air rushes in to expand the lungs during the act of inspira- tion ; when forcibly contracted, it may act as an assistant to the abdominal expiratory mus- cles by diminishing the size of the base of the chest ; by its action on the abdominal viscera it aids in the expulsion of fasces and urine ; in ordinarily tranquil breathing the diaphragm is sufficient for the performance of the function. In animals the extent and position of the dia- phragm vary according to the number of the ribs ; in those whose ribs extend nearly to the pelvis, as in the horse, the thoracic convexity of the diaphragm is much greater than in man.